Restraint Device

This application claims priority to Japanese Patent Application No. 2024-208723 filed on Nov. 29, 2024. The disclosure of the above-identified application, including the specification, drawings, and claims, is incorporated by reference herein in its entirety.

The present disclosure relates to a restraint device.

Japanese Unexamined Patent Application Publication No. 2018-098211 (JP 2018-098211 A) discloses a secondary battery in which a plurality of unit cell layers are stacked. Secondary battery electrodes that are included in the secondary battery include a current collector, and an electrode layer that is disposed on a surface of the current collector. A gas channel is formed in the electrode layer.

Although not described in the aforementioned JP 2018-098211 A, there are cases in which secondary batteries (power storage modules) are restrained in a stacking direction. In this case, it is conceivable that the gas channel might be crushed by a restraint load. There is a concern that as a result of this, gas might accumulate inside the battery, causing deterioration of battery performance.

The present disclosure has been made to solve the above-described problem, and an object thereof is to provide a restraint device that is capable of suppressing a gas channel of an electrode layer from being crushed.

A restraint device according to an aspect of the present disclosure is a restraint device for restraining a power storage module, the restraint device including an elastic member that is stacked with the power storage module in a stacking direction, in a state in which the power storage module is restrained, and a pressing member that presses the elastic member toward the power storage module. The power storage module includes an electrode plate. The electrode plate includes a current collector, and an electrode layer that is stacked with the current collector in the stacking direction. A gas channel is fashioned in the electrode layer. The elastic member includes a first elastic portion, and a second elastic portion that is softer than the first elastic portion. The first elastic portion is provided at a first position not overlapping the gas channel in the stacking direction. The second elastic portion is provided at a second position overlapping the gas channel in the stacking direction.

According to the present disclosure, a gas channel of an electrode layer can be suppressed from being crushed.

An embodiment of the present disclosure will be described in detail below with reference to the drawings. The same or corresponding portions are denoted by the same signs throughout the drawings, and description thereof will not be repeated.

100 100 1 4 FIGS.to A restraint deviceaccording to the embodiment of the present disclosure will be described with reference to. The restraint deviceis a jig that restrains power storage modules during a manufacturing process of a power storage device. Note that the power storage modules may be, for example, secondary batteries such as lithium-ion batteries or the like.

1 FIG. 1 FIG. 200 1 100 100 1 1 is a perspective view schematically illustrating a power storage unitthat is made up a stackand the restraint device. In, the restraint devicerestrains the stack. Note that in the present specification, a Z direction is a stacking direction of the stack. Also, an X direction and a Y direction are each directions orthogonal to the Z direction. The X direction and the Y direction are orthogonal to each other in a plane that is orthogonal to the Z direction. Note that the Z direction is an example of the “stacking direction” in the present disclosure.

100 10 20 30 40 100 1 1 10 20 The restraint deviceincludes end platesand, and restraint membersand. The restraint deviceapplies a restraint load to the stackin the Z direction. Applying an appropriate restraint load to the stackappropriately maintains inter-electrode distances in the power storage modules. As a result, deposition of metal (e.g., lithium) on an electrode (anode) of the power storage module can be suppressed. Note that each of the end plateand the end plateis an example of “pressing member” in the present disclosure.

1 10 20 10 1 1 20 2 1 The stackis sandwiched between the end plateand the end platein the Z direction. The end plateis disposed on a Zside with respect to the stack. The end plateis disposed on a Zside with respect to the stack.

30 1 1 40 1 2 The restraint memberrestrains an end portion of the stack, on an Xside thereof, in the Z direction. The restraint memberrestrains an end portion of the stack, on an Xside thereof, in the Z direction.

2 FIG. 200 1 1 80 90 2 3 1 80 90 2 3 2 3 illustrates a disassembled perspective view of the power storage unit. The stackis formed in a cuboid shape, for example. The stackincludes at least one power storage module, at least one interposition module, and elastic sheetsand. In the present embodiment, the stackincludes a plurality of the power storage modulesand a plurality of the interposition modules. Note that the elastic sheetsandare made of urethane, for example. The elastic sheetsandhave insulating properties.

80 90 80 90 80 2 3 The power storage modulesare arranged in the Z direction. The interposition modulesare disposed between the power storage modulesthat are arrayed in the Z direction. Also, interposition modulesare also disposed between the power storage modulesand each of the elastic sheetand the elastic sheet.

90 90 90 1 90 90 2 90 80 1 80 The interposition modulesare electrically conductive. Specifically, the interposition moduleseach include a current collector plate that is omitted from illustration. This current collector plate is electrically connected to a power source that is omitted from illustration, and is supplied with an electric current from the power source. For example, the current collector plate that is included in the interposition modulethat is closest to the Zside among the multiple interposition modulesmay be electrically connected to one of a positive pole and a negative pole of the power source, and the current collector plate that is included in the interposition modulethat is closest to the Zside among the multiple interposition modulesmay be electrically connected to the other of the positive pole and the negative pole of the power source. Thus, each of the power storage modulesin the stackis charged. Note that the method of charging the power storage modulesis not limited to the above example.

2 10 1 2 10 1 3 20 1 3 20 1 2 3 1 The elastic sheetis disposed between the end plateand the stack. The elastic sheetis sandwiched between the end plateand the stackin the Z direction. The elastic sheetis disposed between the end plateand the stack. The elastic sheetis sandwiched between the end plateand the stackin the Z direction. The elastic sheetsandenable a uniform restraint load to be applied to the stack.

10 20 1 10 1 2 20 1 1 10 20 10 1 10 1 20 1 20 2 The end platesandapply pressure to the stackin the Z direction. Specifically, the end plateapplies pressure to the stacktoward the Zside, and the end plateapplies pressure to the stacktoward the Zside. The end platesandare plate-shaped members. The end platehas a rectangular shape covering the stack, as viewed in plan view from a position away from the end plateon the Zside. The end platehas a rectangular shape covering the stack, as viewed in plan view from a position away from the end plateon the Zside.

10 11 12 13 11 12 11 12 11 12 The end plateincludes a first plate, a second plate, and a plurality of ribs. The first plateand the second plateare arranged in the Z direction. The first plateand the second plateface each other in the Z direction. Note that the first platehas the same shape and size as those of the second plate.

13 11 12 11 12 13 13 13 Each of the ribsis provided between the first plateand the second plate. The first plateand the second plateare linked by the ribs. Each of the ribsextends in the X direction. The ribsare arranged at intervals in the Y direction.

11 11 11 11 11 1 11 11 2 a b a b The first plateis formed with a plurality of (five in the present embodiment) notches, and a plurality of (five in the present embodiment) notches. The notchesare provided arrayed along a side of the first plateon the Xside. The notchesare provided arrayed along a side of the first plateon the Xside.

12 12 11 11 12 11 b b b b The second platehas a plurality of notchesthat is formed so as to be provided below the notchesof the first plate. That is to say, the notchesoverlap the notchesin the Z direction.

2 FIG. 12 11 11 11 a a Although not illustrated in, the second platehas a plurality of notches that is formed so as to be provided below the notchesof the first plate. These notches overlap the notchesin the Z direction.

20 10 20 21 22 23 21 21 21 22 22 21 a b b a The end platehas the same configuration as that of the end plate. That is to say, the end plateincludes a first plate, a second plate, and a plurality of ribs. The first plateis formed with a plurality of notchesand a plurality of notches. The second plateis formed with a plurality of notchesand a plurality of notches (omitted from illustration) overlapping the notchesin the Z direction.

30 40 1 1 30 40 30 1 1 40 2 1 30 40 40 The restraint membersandare arranged at a distance from each other in the X direction, with the stacksandwiched therebetween. Pressure is applied to the stackin the Z direction by being sandwiched between the restraint membersand. The restraint memberis disposed on the Xside of the stack. The restraint memberis disposed on the Xside of the stack. The restraint memberhas the same shape as the restraint member. Accordingly, just the configuration of the restraint memberwill be described in detail below.

40 41 42 41 41 41 41 41 41 41 a b a b a b The restraint memberincludes a frameand a plurality of columnar members. The framehas an upper frameand a lower frame. The upper frameand the lower frameare arranged across an interval in the Z direction. Each of the upper frameand the lower frameextends in the Y direction.

42 41 41 42 41 41 a b a b. The columnar membersare arranged at intervals in the Y direction, between the upper frameand the lower frame. Each of the columnar membersextends in the Z direction and also connects the upper frameand the lower frame

40 1 42 11 12 21 22 41 11 11 41 22 22 1 10 20 41 41 b b b b a c b c a b. In a state in which the restraint memberis restraining the stack, each of the columnar memberspasses through the notches,,, andthat are provided overlapping each other in the Z direction. In this state, a lower face of the upper framecomes into contact with an upper faceof the first plate. An upper face of the lower framecomes into contact with a lower faceof the second plate. Accordingly, the stack, the end plate, and the end plateare sandwiched between the upper frameand the lower frame

30 31 32 31 31 31 a b. The restraint memberincludes a frameand a plurality of columnar members. The framehas an upper frameand a lower frame

30 1 32 11 21 12 22 31 11 11 31 22 22 1 10 20 31 31 a a a c b c a b. In a state in which the restraint memberis restraining the stack, each of the columnar memberspasses through the notchesandthat are arranged in the Z direction, and notches that are omitted from illustration, formed in each of the second plateand the second plate. In this state, a lower face of the upper framecomes into contact with the upper faceof the first plate. An upper face of the lower framecomes into contact with the lower faceof the second plate. Thus, the stack, the end plate, and the end plateare sandwiched between the upper frameand the lower frame

100 70 71 72 73 The restraint deviceincludes a protective member, a protective member, a protective member, and a protective member.

70 71 30 40 11 11 70 31 71 41 c a a. Each of the protective memberand the protective memberis disposed between the restraint memberand the restraint member, and is also fixed to the upper faceof the first plate. The protective memberextends in the Y direction along the upper frame. The protective memberextends in the Y direction along the upper frame

72 73 30 40 22 22 72 31 73 41 c b b. Each of the protective memberand the protective memberis disposed between the restraint memberand the restraint member, and is also fixed to the lower faceof the second plate. The protective memberextends in the Y direction along the lower frame. The protective memberextends in the Y direction along the lower frame

3 FIG. 2 FIG. 1 90 91 80 91 80 10 20 1 91 90 91 is a partially enlarged view illustrating a cross-section of the stack. The interposition moduleincludes an elastic memberfor making planar pressure that is applied to the power storage moduleto be uniform. The elastic memberis pressed toward the power storage moduleby the end plate() (). Note that in order to ensure electrical conductivity in the stack, a conductive sheet member or the like may be disposed on a surface of the elastic member. This electrically connects the current collector (omitted from illustration) that is included in the interposition moduleto the elastic member.

3 FIG. 80 80 As illustrated in, the power storage moduleis a bipolar type power storage unit. Note that the power storage modulemay be a monopolar type power storage unit.

80 81 82 83 81 83 82 81 83 82 80 81 83 a The power storage moduleincludes a plurality of electrode plates, a plurality of separators, a cathode terminal electrode plate, and an anode terminal electrode plate (omitted from illustration). The electrode plates, the cathode terminal electrode plate, and the anode terminal electrode plate are stacked in the Z direction, with the separatorsinterposed therebetween. The electrode plates, the cathode terminal electrode plate, the anode terminal electrode plate, and the separators, make up a stacked electrode assembly. Note that the electrode plateand the cathode terminal electrode plateare each an example of “electrode plate” of the present disclosure.

81 83 81 81 84 85 86 85 Each of the electrode platesis disposed between the cathode terminal electrode plateand the anode terminal electrode plate (omitted from illustration). The electrode platesare bipolar electrodes in the present embodiment. Each of the electrode platesincludes a current collector, a cathode layer, and an anode layer. Note that the cathode layeris an example of “electrode layer” of the present disclosure.

81 86 84 1 84 81 85 84 2 84 a b In the electrode plate, the anode layeris provided on a principal faceon the Zside of the current collector. In the electrode plate, the cathode layeris provided on a principal faceon the Zside of the current collector.

83 80 1 83 84 85 83 86 85 84 84 85 84 84 91 84 84 83 80 2 a b a The cathode terminal electrode plateis situated at an end portion of the power storage moduleon the Zside. The cathode terminal electrode plateincludes the current collectorand the cathode layer. In the cathode terminal electrode plate, the anode layerand the cathode layerare not provided on the principal faceof the current collector, and the cathode layeris provided on the principal faceof the current collector. The elastic memberis disposed on the principal faceof the current collectorof the cathode terminal electrode plate. Note that the anode terminal electrode plate, which is omitted from illustration, is situated at an end portion of the power storage moduleon the Zside.

85 85 81 85 83 Note that the following description of the cathode layerapplies to both the cathode layerof the electrode plateand the cathode layerof the cathode terminal electrode plate.

80 87 87 80 87 81 a The power storage moduleincludes a resin sealant. The resin sealantis provided so as to seal the perimeter of the stacked electrode assembly. The resin sealantseals internal space that is formed between two electrode platesthat are adjacent to each other. An electrolytic solution is injected into this internal space.

88 85 80 88 88 80 87 86 A gas channelis formed in the cathode layer. Gas that is generated in the power storage moduleflows through the gas channel. The gas that has flowed through the gas channelis externally discharged from the power storage module, from a discharge port, omitted from illustration, that is formed in the resin sealant. Note that the gas channel may be formed in the anode layer.

88 88 88 88 88 88 88 a b a b a b The gas channelincludes a gas channeland a gas channel. The gas channeland the gas channelcommunicate with each other. Note that the gas channeland the gas channelare examples of “first gas channel” and “second gas channel” of the present disclosure, respectively.

88 81 83 88 85 87 88 81 83 88 85 85 86 a a b b The gas channelextends along an outer peripheral edge portion of the electrode plate(cathode terminal electrode plate). The gas channelis a groove that is formed between the outer peripheral edge portion of the cathode layerand the resin sealant. The gas channelis formed on an inner side from the outer peripheral edge portion of the electrode plate(cathode terminal electrode plate). The gas channelis a groove that is formed between portions of the cathode layer. Note that the gas channels may be formed, for example, from through holes formed in the cathode layer(anode layer).

85 88 84 84 88 88 84 82 88 84 85 The cathode layeris not provided between the gas channeland the current collector. That is to say, the current collectoris exposed at a portion at which the gas channelis provided. In the portion at which the gas channelis provided, the current collectorand the separatorface each other. Note that in the portion at which the gas channelis provided, the current collectordoes not necessarily have to be exposed, due to a thin film of the cathode layerbeing provided.

91 91 91 91 91 91 91 91 91 91 91 a b b a b a b a a b The elastic memberincludes an elastic portionand an elastic portion. The elastic portionis softer than the elastic portion. Specifically, the elastic portionexhibits a greater deformation amount than the elastic portion, when the same load is applied. In other words, the elastic portionrequires a smaller load to be deformed by the same amount, as compared with the elastic portion. The elastic portionand the elastic portionare examples of “first elastic portion” and “second elastic portion” of the present disclosure, respectively.

91 91 91 91 a b a b The elastic portionis made of the same material as that of the elastic portion. Specifically, each of the elastic portionand the elastic portionis made of a foaming urethane resin.

100 91 91 a b This allows the number of types of parts of the restraint deviceto be reduced, as compared with when the elastic portionand the elastic portionare made of different materials.

91 91 91 91 91 91 91 91 91 91 91 91 91 a b c c b c a b a c b c a. Each of the elastic portionand the elastic portioncontains a foaming agent. In the present embodiment, density of the foaming agentin the elastic portionis higher than density of the foaming agentin the elastic portion. This makes the elastic portionto be softer (less rigid) than the elastic portion. For example, the density of the foaming agentin the elastic portionmay be twice or more the density of the foaming agentin the elastic portion

91 91 c Thus, adjusting the density of the foaming agentfor each portion enables a plurality of portions, each having different hardness from each other, to be easily formed in the elastic member.

Here, in a conventional restraint device, it is conceivable that the gas channel may be crushed by the restraint load. There is a concern that as a result of this, gas might accumulate inside the battery, causing deterioration of battery performance.

91 1 88 91 2 88 1 2 a b Accordingly, in the present embodiment, the elastic portionis provided at a position Pthat does not overlap the gas channelin the Z direction. The elastic portionis provided at a position Poverlapping the gas channelin the Z direction. Note that the position Pand the position Pare examples of “first position” and “second position” in the present disclosure.

91 2 88 88 80 88 b Thus, the elastic portion, which is relatively soft, is disposed at the position Poverlapping the gas channelin the Z direction, and accordingly pressure that is applied to the gas channelwhen the power storage moduleis restrained can be made to be relatively small. As a result, the gas channelcan be suppressed from being crushed.

91 88 b The elastic portionis disposed in a range overlapping the entire range in which the gas channelis provided, in the Z direction.

91 91 91 81 83 81 83 91 88 91 81 83 81 83 91 88 91 91 b d e d a d e b d e The elastic portionincludes a portionand a portion. Viewing the electrode plate(cathode terminal electrode plate) from a position P away from the electrode plate(cathode terminal electrode plate) in the Z direction, the portionextends along the gas channel. That is to say, the portionextends along the outer peripheral edge portion of the electrode plate(cathode terminal electrode plate). Viewing the electrode plate(cathode terminal electrode plate) from the position P, the portionextends along the gas channel. Note that the portionand the portionare examples of “first portion” and “second portion” according to the present disclosure, respectively.

88 88 91 a b This enables the gas channeland the gas channelto each be suppressed from being crushed by the elastic member.

81 83 85 85 88 a Viewing the electrode plate(cathode terminal electrode plate) from the position P, the cathode layerhas an adjacent portionthat is adjacent to the gas channel.

91 2 3 85 b a The elastic portionextends from the position Pto positions Pat which it overlaps the adjacent portionin the Z direction.

91 3 85 88 88 b a Thus, the elastic portionextends to the positions Pat which it overlaps the adjacent portionthat is adjacent to the gas channelin the Z direction, and accordingly the gas channelcan be more reliably suppressed from being crushed.

91 91 2 3 91 1 91 91 3 1 2 2 d b e b 3 FIG. Specifically, the portionof the elastic portionextends from the position Pto the position Pon the opposite side from an outer peripheral edge portion of the elastic member(Yside in). Furthermore, the portionsof the elastic portionextend to the positions Pthat are provided on both ends (Yside and Yside) of the position P.

2 3 Note that the width of the position Pin the Y direction may be larger than the width of the position Pin the Y direction.

4 FIG. 4 FIG. 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 91 1 91 91 91 2 d b d f g f g d h i h i h f g i f g illustrates a planar cross-section of the elastic member. As illustrated in, the portionof the elastic portionis formed in an annular shape. Specifically, the portionincludes a sideand a sidethat are arranged in the X direction. Each of the sideand the sideextends in the Y direction. The portionincludes a sideand a sidethat are arranged in the Y direction. Each of the sideand the sideextends in the X direction. The sideconnects end portions of each of the sideand the sideon the Yside to each other. The sideconnects end portions of each of the sideand the sideon the Yside to each other.

91 91 91 91 91 91 91 91 91 b e e e f g e h i. The elastic portionincludes a plurality of the portions. Each of the portionsextends in the X direction. Each of the portionsconnects the sideand the side. The portionsare arranged in the Y direction at intervals from each other, between the sideand the side

4 FIG. 91 91 91 91 91 91 91 91 91 91 91 a e a f g b a a e f g As illustrated in, each of the elastic portionsis disposed in a space between adjacent portionsthat are arrayed in the Y direction. Also, each of the elastic portionsis disposed in a space between the sideand the side. The elastic portionand each of the elastic portionsmay be provided separately (may be separate bodies). In this case, each of the elastic portionsmay be joined (e.g., bonded with an adhesive or the like) to at least one of the portionsadjacent in the Y direction and the side(side) adjacent in the X direction.

91 1 88 91 2 88 88 91 91 88 a b a As described above, in the present embodiment, the elastic portionsare provided at the position Pthat does not overlap the gas channelin the Z direction, and the elastic portionis provided at the position Pthat overlaps with the gas channelin the Z direction. Thus, the gas channelcan be suppressed from being pressed by the relatively hard (high rigidity) elastic portionof the elastic member. As a result, the gas channelcan be suppressed from being crushed.

88 91 b Also, even when the gas channelis crushed, the elastic portionthat is relatively soft (with low rigidity) can be expanded by the gas. As a result, obstruction of the gas flow can be suppressed.

100 In the above embodiment, an example has been described in which the restraint deviceis used during the manufacturing process of the power storage module, but the present disclosure is not limited to this. For example, a power storage unit (power storage device) in a state in which power storage modules are restrained by a restraint device may be installed in electronic equipment such as an electrified vehicle or the like.

300 310 320 330 340 350 360 330 310 340 320 310 320 310 320 5 FIG. 5 FIG. For example, a restraint devicethat is illustrated inincludes end platesand, insulating filmsand, bolts, and nuts. The insulating filmis disposed on a lower face of the end plate. The insulating filmis disposed on an upper face of the end plate. Note that for simplification, in, the end plateand the end plateare each represented by an open block. Also, each of the end plateand the end plateis an example of “pressing member” in the present disclosure.

1 330 340 90 330 340 400 90 340 500 90 330 400 500 90 The stackis disposed between the insulating filmand the insulating film. Interposition modulesare disposed on a lower face of the insulating filmand on an upper face of the insulating film. A cathode terminalis connected to the interposition modulethat is disposed on the upper face of the insulating film. An anode terminalis connected to the interposition modulethat is disposed on the lower face of the insulating film. Note that each of the cathode terminaland the anode terminalis connected to a current collector plate, omitted from illustration, included in the interposition module.

350 360 310 320 350 351 352 352 351 352 310 351 360 The boltsand the nutslink the end plateand the end platetogether. Each of the boltsincludes a shaft portionand a head. The headis provided at an upper end portion of the shaft portion. The headis disposed on an upper face of the end plate. The shaft portionhas a groove formed thereon that corresponds to the nut.

351 350 311 310 321 320 360 351 320 350 360 1 The shaft portionof the boltpasses through a through holethat is formed in the end plateand a through holethat is formed in the end plate. The nutis attached to a lower end portion of the shaft portionand is disposed on a lower face of the end plate. Thus, the boltand the nutapply a restraint load to the stackin the Z direction.

91 91 91 91 91 91 91 91 91 a b a b a b a b In the above embodiment, an example has been described in which each of the elastic portionsis provided separately from the elastic portion, but the present disclosure is not limited to this. Each of the elastic portionsmay be integrally formed with the elastic portion. That is to say, the elastic membermay be a single member including a plurality of the elastic portionsand the elastic portion. In other words, the elastic portionsand the elastic portionmay be formed continuously.

91 91 91 91 a b b a In the above embodiment, the elastic portionsand the elastic portionare made of the same material, but the present disclosure is not limited to this. The elastic portion(second elastic portion) may be made of a material that is softer (has lower rigidity) than that of the elastic portions(first elastic portion).

91 In the above embodiment, an example has been described in which the elastic memberis a foaming member, but the present disclosure is not limited to this. The elastic member may be made of a material that is different from the foaming member. For example, the elastic member may be made of silicone rubber or the like. In this case, the first elastic portion, and the second elastic portion that is softer than the first elastic portion, may be formed by adjusting the amount and type of additive that is added to the silicone rubber, or the like.

91 91 91 91 91 91 b d e b d e. In the above embodiment, an example has been described in which the elastic portionincludes the portionand the portions, but the present disclosure is not limited to this. The elastic portionmay include just one of the portionand the portions

The embodiment that is disclosed herein should be considered to be exemplary in all respects and not restrictive. The scope of the present disclosure is indicated by the claims rather than the description of the embodiment described above, and it is intended that all changes within the meaning and scope equivalent to the claims are included.